Creating spatial representations of the world for use in decision-making, navigation and many other applications, has grown into an enormous GIS (Geographical Information System, or sometimes, Global Information System) that links natural and man-made features with their relative and unique 3-D positions on or near Earth. Data include Earth topography and vegetation, as mostly gathered by satellite imagery. Other Features, such as the centerline of a road, are gathered by driving a vehicle with a GPS (Global Positioning System) system and noting the location of intersections and waypoints. Utility locations are input by surveying with GPS. Collected into GIS databases, the data subsequently are used for vehicle navigation, building operations, emergency response, environmental health, and a wide variety of other applications.
In one potential use of GIS data, the US Military has declared that one-third of its forces need to be robotic by 2015. Globally positioned Maps (maps referenced to the GIS) are the most efficient, seamless means for indoor and outdoor navigation by military and other robots. One problem with creating such maps, however, is that GPS currently is not pervasive. It is not available indoors or wherever GPS satellite signals are blocked or weak, such as in areas with heavy forestation or in dense urban areas such as older sections of European and Asian cities. While methods exist that estimate and extrapolate GPS coordinates through signal-less spaces, these result in significant errors in GPS-poor outdoor regions.
Indoors, GPS is not used, so few up-to-date, automated “as-built” building interior floor plans exist, globally positioned or not. Instead, if a Map of a building exists at all, it typically is a vector-based CAD drawing by the designing architect. Since buildings rarely are built exactly as specified by the architect, the CAD drawing of the interior spaces usually does not even fit the building's actual exterior footprint. Remodeling and additions, both interior and exterior, rarely get included in the Map.
A wide range of mapping techniques exist, including for example, those described in U.S. Pat. No. 6,009,359 to El-Hakim et al. In this patent, the invention relates to a method of model generation and, more particularly, to a method of generating three-dimensional maps from range and intensity images created from by an imaging device and dead reckoning. This method requires enormous amounts of computer processing, which slows results. In addition, visual pattern-matching techniques are not exact, so inaccuracies result. Further, the maps generated are not related to GIS coordinate systems, so the resulting map is not usable within a GIS context. By this method, data gathered without GPS coordinates cannot be spatially associated.
U.S. Pat. No. 6,917,893 to Dietsch et al. describes a highly accurate spatial data collection apparatus for use in creating floor plans, maps and models of existing spaces. No methods are disclosed, however, for generating these maps in GIS space to provide for seamless navigation to outdoor spaces.
In fact, most common methods currently used for creating GIS Maps of GPS-poor spaces are manual: teams of people using various hand measuring devices, including tape measures and single-beam laser range finders. Linear measurements of each room are taken typically from only two points on each opposing surface; thus, in a rectangular room, the lengths of two sides of the rectangle would be the only measurements taken and not directly related to an adjoining room's measurements. Corners are assumed to be 90 degrees. The individual room measurements are then entered by hand into software that draws the building based on a “best fit” of the measurements. Because buildings are not perfectly square and measurements are not perfectly level, cumulative error results in a building's interior appearing to be larger or smaller than its exterior. Relating such measurements to exterior GIS coordinates is thus difficult. Further, indoor Features must be identified manually and separately with their GPS positions calculated in the mapped space, which is a very time consuming process.